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Biomedical subjects

J Mandel

Publications and source records attributed to J Mandel.

At least 19 recordsLinked to original sources
PubMed1995

Calcium supplementation and rectal mucosal proliferation: a randomized controlled trial.

BACKGROUND: Data from studies using rodents suggest that dietary calcium inhibits bile acid-induced mucosal damage and experimental carcinogenesis in the large bowel. However, in humans, the effect of dietary calcium and calcium supplementation on proliferation and carcinogenesis in the large bowel has been unclear. PURPOSE: To assess the effect of calcium supplementation on rectal mucosal proliferation in humans, we conducted a multicenter, randomized, placebo-controlled, double-blinded trial. METHODS: Participants were part of a larger multicenter chemoprevention trial; all were at high risk for large-bowel neoplasia, with at least one large-bowel adenoma removed endoscopically within the 3 months before study entry but with no known polyps remaining. Subjects were randomly assigned to receive daily either 3000 mg of calcium carbonate (providing 1200 mg elemental calcium) or an identical-appearing placebo tablet. During a scheduled endoscopy 6-9 months after random assignment (approximately 1 year after the qualifying endoscopy), rectal mucosal samples were obtained from 333 patients (173 assigned to calcium and 160 assigned to placebo). Proliferating cell nuclear antigen (PCNA) labeling indices (LIs) were computed as the measure of proliferation in specimens from 146 patients receiving calcium and 129 patients receiving placebo. Bromodeoxyuridine (BrdU) labeling was used to measure proliferation in a smaller number of specimens (27 calcium-receiving and 31 placebo-receiving participants). For each scorable crypt having at least one labeled cell (or surrounded by crypts with at least one labeled cell), a crypt LI was calculated as the number of labeled cells divided by the total number of crypt cells. Crypt LIs were averaged to produce a participant's average LI. RESULTS: The overall unadjusted mean PCNA LIs (+/- SE) were similar in the calcium and placebo groups (3.85% +/- 0.08% versus 3.92% +/- 0.08%, respectively, P = .30). The overall unadjusted mean BrdU LIs (+/- SE) were 3.88% +/- 0.30% in the calcium group and 3.54% +/- 0.21% in the placebo group (P = .54). PCNA labeling indices in the most luminal 40% of the crypt were small but, if anything, were higher in the calcium group. There was no patient subgroup within which calcium had an antiproliferative effect; the overall findings persisted among patients with high and low calcium intake, high and low fat intake, and high and low fiber intake. CONCLUSIONS: Calcium supplementation does not decrease rectal mucosal proliferation, as measured by PCNA (and BrdU) immunohistochemistry, in patients with previous large-bowel adenomas. This study, therefore, does not provide evidence for an anticarcinogenic effect of calcium.

Adenoma↗
PubMed1995

p53 and disease progression in patients with non-small cell lung cancer.

Present methods of predicting nodal progression preoperatively in patients with non-small cell lung cancer (NSCLC) are inadequate. Our hypothesis was that p53 expression in primary NSCLC would predict disease progression, making it a useful marker of adverse outcome. From 1987 to 1992, sixty-eight consecutive NSCLC patients underwent potentially curative lung resection and mediastinal lymph node dissection by one surgeon. Primary tumours were analysed using the p53 monoclonal antibody 1801. p53 overexpression was found in 53% of tumours. p53 expression did not correlate with age, gender, histology or stage. A trend toward a higher incidence of p53 expression was seen in tumours with nodal spread (P = 0.06), and p53 expression correlated significantly (P = 0.03) with improved disease-free survival in patients with squamous cell carcinoma (SCC). p53 was the fourth most important independent predictor of survival, behind histology, gender and nodal disease. As a weak independent predictor of survival, the correlation of p53 expression with survival in patients with SCC must be evaluated with caution. If borne out in a larger patient population, p53 expression may be a marker of nodal disease progression in patients with NSCLC.

Biomarkers, Tumor↗
PubMed1995

Imipramine binding to blood platelets and aggressive behavior in offenders, schizophrenics and normal volunteers.

The relationships between [3H]imipramine binding to blood platelets and manifestation of aggressive behavior was studied in three different groups of subjects. Arrested offenders displayed high imipramine binding compared to controls, with violent offenders exceeding their nonviolent counterparts. Hostile schizophrenic patients showed imipramine binding higher than nonhostile matched patients. In normal volunteers, on the other hand, no correlation between imipramine binding and scores of aggression was found. The results support the notion about the involvement of a neuronal serotonergic system in the regulation of aggressive behavior. The contribution of this biological factor is detectable in pathological manifestation of aggression but not in normal behavior.

Adolescent↗
PubMed1992

AIDS education for hospital workers in Manila: effects on knowledge, attitudes, and infection control practices.

OBJECTIVE: To evaluate an AIDS education intervention for health workers in Metro Manila hospitals. METHODS: A randomized controlled education program consisting of lectures, role-plays, posters and pamphlets was delivered to physicians, nurses, laboratory technologists and orderlies in Manila hospitals. Knowledge, attitudes and infection control practices were measured before, immediately after, and 2 months after the intervention. RESULTS: Baseline survey among 641 hospital workers revealed poor knowledge, negative attitudes towards AIDS patients, and inappropriate infection control practices. Immediately after the intervention, there was significant improvement in (1) knowledge scores (8.7-11.2 in the intervention group versus 8.5-9.5 in the control group; range, 0-14), (2) attitude scores (54.4-60.6 versus 54.6-56.8; range, 22-88), and (3) needle-recapping practices (14-43% versus 39-43%) (all P values < 0.001). After 2 months, attitude scores in the experimental group fell to the same level as those of the control group, while improvements in knowledge and needle recapping were largely maintained. Role-playing was considered by the participants to be the most effective component of the intervention. CONCLUSIONS: These results suggest that AIDS training for hospital workers in the Philippines and in similar countries is necessary and can be effective. Ideally, such training should include role-playing and should be ongoing in order to sustain the effect.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Long-term results of dialysis and transplantation in patients with end-stage renal failure from hypernephroma.

We analyzed long-term, 2- to 9-year results and risk factors in 13 patients treated with dialysis and transplantation for hypernephroma. Eight were dialyzed only, 6 died, 4 of them from metastatic disease that occurred in less than 8 months in 3. Five patients were also transplanted. Three died, 1 of metastatic disease. Two are alive, 1 with metastatic disease, 6 years after transplant, 3 years after diagnosis of metastasis. There were no differences in age and sex in those with early metastatic disease when compared to those without, but stage III-IV disease and time of less than 5 years between first and second nephrectomy were more common in those with early metastatic disease. These data indicate that a 7-month waiting time on dialysis is enough to avoid transplanting those with early recurrence, and that patients with stage III-IV and early reappearance of tumor in the second kidney are best treated with conservative management rather than a second total nephrectomy.

Adult↗
PubMed1984

Benefits versus risks in conservation surgery with irradiation for breast cancer.

This report analyzes the survival and complications inherent in the conventional treatment of breast cancer, radical mastectomy, and the more conservative procedure, conservation surgery with irradiation. Both procedures have benefits and risks. The benefits as measured by survivorship appear to be approximately the same. The major benefit of conservation surgery with irradiation is that the breast is left intact. The possible complication of irradiation carcinogenesis is addressed, and the literature analyzed. This review indicates that the absolute risk of breast cancer developing in the second breast is not nearly as great as originally thought. It is concluded that if a woman with breast cancer is a candidate for either mastectomy or the conservative procedure, it is the clinician's obligation to objectively present the evidence regarding the benefits and risks of these procedures.

Breast Neoplasms↗
PubMed1982

Comparison of two isotope dilution/mass spectrometric methods for determination of total serum cholesterol.

Isotope dilution/mass spectrometric methods for total serum cholesterol, developed separately at the Karolinska Institutet (KI) and the National Bureau of Standards (NBS), were compared by applying them to a common set of serum pools. A search for the cause of a systematic difference of a few percent in results from the two methods revealed that the KI cholesterol standard contained lathosterol, which interfered with the calibration of the method. With NBS Standard Reference Material cholesterol used for new analyses at the KI, the average difference in mean values dropped to 0.2%. The NBS results are more precise. This is attributed to the protocols NBS used for sample preparation and mass spectrometry. However, these protocols make the NBS method more complex and time-consuming. A recent critical article on the use of this technique for total cholesterol is also examined.

Cholesterol↗
PubMed1981

A multilaboratory-evaluated reference method for the determination of serum sodium.

We carried out a statistically designed, multilaboratory study to evaluate a flame atomic emission spectroscopic (FAES) method for serum sodium as a Reference Method. definitive values for the serum pools for the study, with sodium in the 110-160 mmol/L range, were determined at the National Bureau of Standards by an ion-exchange/gravimetry method. The multilaboratory FAES results were judged against the preselected performance criteria for the Reference Method: maximum imprecision 1.5 mmol/L, maximum bias 2.0 mmol/L. The standard error of a single laboratory's performance of the method varied with concentration from 0.46 to 0.86 mmol/L with a maximum bias of 1.0 mmol/L; thus, the criteria were satisfied. The cooperating laboratories performed the method with either manual or semi-automated pipetting. Although both modes of pipetting satisfied our acceptability criteria, only the method with semi-automated pipetting is described here as the Reference Method. The statistical results indicate that the precision criterion can be fulfilled with fewer than four replicate analyses.

Humans↗
PubMed1980

DAWN: a second look--its impact on minorities and public policy.

Though various indicators yield different statistics about the minority component of drug problems, Blacks and Hispanics dominate opiate statistics of major data systems. This dominance increases when major consequences--chemotherapy, arrest and, especially, imprisonment--are measured. Drug Abuse Warning Network (DAWN) figures were cited as the exception, but this was due to weaknesses in DAWN reporting and its analysis by experts. Excluding unreliable and unrepresentative crisis center mentions, estimating the Hispanic component of "White" DAWN mentions, and separating opiates from other drugs, the DAWN statistics are very similar to CODAP and arrest statistics. "Hard drugs" remain an essentially minority phenomena.

Black or African American↗
PubMed1980

Statistics blur minority distinctiveness.

In their study of the success of drug treatment, Sirotnik and Roffe blurred and probably minimized racial and ethnic distinctions. Their problem was trying to compare Whites, Blacks, and Chicanos with a statistic requiring two-art or scalar variables. Of non-Blacks (compared to Blacks), 29% were Chicanos, and of non-Browns (compared to Chicanos), 32% were Blacks. Nonetheless, of nine variables significantly associated with "staying in treatment," five were blackness, brownness, or synonymous with them. A format with only percentages would enable analysis to see substantive results clearly and in more detail.

Ethnicity↗
PubMed1980

Total serum cholesterol by isotope dilution/mass spectrometry: a candidate definitive method.

We describe a highly accurate and precise method for determination of total cholesterol in serum by isotope dilution/mass spectrometry. The method was developed for a Study Group of the Committee on Standards of the American Association for Clinical Chemistry, for use in establishing the accuracy of a candidate reference method for total cholesterol, and fulfills their criteria for a definitive method. Cholesterol-d7 is added to serum, with the weight ratio of cholesterol-d7 to total serum cholesterol kept near to 1:1. The esters are hydrolyzed and the cholesterol is separated and converted into the trimethylsilyl ether derivative for measurement by combined gas chromatography/mass spectrometry. The intensity ratio of the molecular ions at m/z 465 and 458 is measured for each sample and for two calibration mixtures, according to a prescribed bracketing protocol. A weight ratio for the sample is obtained by linear interpolation of the ion-intensity ratios, and the total cholesterol is then calculated. The method was applied four times over several weeks to each of five serum pools. Statistical analysis involving consideration of both replication error and variability between weeks gave a coefficient of variation for a single measurement of 0.36%. The absence of interferences in the method was demonstrated by measurements at several other masses.

Carbon Radioisotopes↗
PubMed1980

The parameterization of predictive value for multisite screening.

In the design of a medical screening program, it is standard practice to employ the parameters of sensitivity and specificity of the test, together with the population disease prevalence, in order to obtain the predictive values of the test. Multiphasic screening, i.e. the use of two or more tests on the same occasion to screen for more than a single disease, has stimulated the need for a formulation of the joint predictive value of these tests employed in combination. In this communication a parameterization of joint predictive value is presented in the context of multisite cancer screening. The resulting parameters are related to the separate disease prevalences, as well as to the sensitivities and specificities of the separate tests, under the assumption of statistical independence among cancer screens.

Humans↗
PubMed1978

Statistical evaluation of CAP survey results for calcium, potassium, and blood urea nitrogen.

Throug the use of the statistical technic known as the linear model, a complete analysis has been made of data obtained in the Colleg of American Pathologists Survey of 1975 for calcium, potassium, and blood urea nitrogen (BUN). The analysis allows a separation of laboratories into core and non-core categories. It also allows for determination of the reproducibility of each analytic technic involved in this survey. For Ca and K, the results obtained by each analytic method were compared with the results obtained by the National Bureau of Standards through use of the definitive method. For BUN, the comparison was made with the average of values for all laboratories and all methods.

Blood Urea Nitrogen↗